EP3077342B1 - Glazing unit comprising a hydrophilic layer having an improved scratch resistance - Google Patents

Description

The present invention relates to a hydrophilic layer glazing, a method of manufacturing the same, and its use.

Visibility through the windows of transport vehicles can be degraded when condensation forms. Known solutions for preventing or eliminating fogging include increasing ventilation or using heated windows. To avoid charging the battery of electric vehicles, in particular, a passive solution is preferable.

The document WO 2013/026612 A1 discloses a glazing comprising a substrate coated with a hydrophilic layer containing at least polyurethane, polyvinylpyrrolidone and a film-forming agent. This glazing delays and limits the formation of condensation in the form of droplets affecting visibility. On the contrary, condensation tends to settle in the form of a uniform film of water that does not affect visibility.

The scratches of the glazing, and in particular of the hydrophilic layer, are, apart from the condensation, one of the main other phenomena that can hinder the visibility through the glazing. The invention therefore aims to improve the scratch resistance of this type of glazing, and in particular of this type of hydrophilic layer.

This object is achieved by the invention which, accordingly, relates to a glazing unit comprising a hydrophilic polyurethane network layer incorporating bisurized functions according to claim 1. For the purposes of the invention, the term "incorporate" means: by bond covalent.

The bisurized functions induce additional physical crosslinking by hydrogen bonding between two hydrogen atoms each connected to a nitrogen atom by a single bond and an oxygen atom of a neighboring molecule, connected to a carbon atom by a double bond. In the sense of the invention, a glazing designates a structure comprising a transparent substrate of glass material such as glass, glass-ceramic, silicon compound such as polysiloxane, crystalline oxide of the alumina-type (sapphire) ..., or of transparent polymer material resistant to the temperatures for producing the hydrophilic layer , in particular 150 ° C. A polycarbonate, a polymethyl methacrylate, an ionomeric resin, a polyamide, a polyester such as polyethylene terephthalate, a polyolefin, etc. can be mentioned. The transparent substrate can constitute a rigid sheet or a flexible film.

The glazing of the invention may be monolithic, but the hydrophilic layer may also coat a transparent substrate forming part of a laminated or multiple glazing (double, triple ...).

• la couche hydrophile contient de la polyvinylpyrrolidone ; les chaines moléculaires, par exemple essentiellement linéaires de polyvinylpyrrolidone, peuvent être enchevêtrées dans le réseau polyuréthane sans y être liées par liaison covalente, par exemple par formation de celui-ci en présence de la polyvinylpyrrolidone ;
• la couche hydrophile contient un agent filmogène, qui contient avantageusement au moins un polydiméthylsiloxane, de préférence modifié par un polyester, en particulier à fonction hydroxy ;
• la couche hydrophile contient au moins 75 à 99 % en masse de polyuréthane, 1 à 15 % en masse de polyvinylpyrrolidone, et 0,01 à 3 % en masse d'agent filmogène ;
• le poids moléculaire moyen en poids de la polyvinylpyrrolidone est de 1,1.10⁶ à 1,8.10⁶ g/mol ;
• la couche hydrophile a une épaisseur comprise entre 0,1 et 250 µm, de préférence 1 et 100 µm, et de manière particulièrement préférée 3 et 50 µm ; et
• la couche hydrophile est reliée à un substrat verrier avec interposition d'un primaire d'adhésion qui contient au moins un aminosilane (voir définition d'un matériau verrier précédemment).

According to other preferred features of the glazing of the invention:

• the hydrophilic layer contains polyvinylpyrrolidone; the molecular chains, for example substantially linear polyvinylpyrrolidone, may be entangled in the polyurethane network without being covalently bonded therein, for example by forming it in the presence of polyvinylpyrrolidone;
• the hydrophilic layer contains a film-forming agent, which advantageously contains at least one polydimethylsiloxane, preferably modified with a polyester, in particular with a hydroxyl function;
• the hydrophilic layer contains at least 75 to 99% by weight of polyurethane, 1 to 15% by weight of polyvinylpyrrolidone, and 0.01 to 3% by weight of film-forming agent;
• the weight average molecular weight of the polyvinylpyrrolidone is 1.1 × 10 ⁶ to 1.8 × 10 ⁶ g / mol;
• the hydrophilic layer has a thickness of between 0.1 and 250 μm, preferably 1 and 100 μm, and particularly preferably 3 and 50 μm; and
• the hydrophilic layer is connected to a glass substrate with the interposition of an adhesion primer which contains at least one aminosilane (see definition of a glass material previously).

1. a) une solution contenant au moins un isocyanate, un polyol et une bisurée à fonction polyol, de la polyvinylpyrrolidone, un agent filmogène et un solvant, est déposée sur un substrat verrier,
2. b) le vitrage contenant le substrat et la solution déposée est séché, et
3. c) soumis à une température comprise entre 100 et 150 °C.

The invention furthermore relates to a method of manufacturing a glazing unit comprising a hydrophilic layer as described above, in which:

1. a) a solution containing at least one isocyanate, a polyol and a polyol-functional bisurea, polyvinylpyrrolidone, a film-forming agent and a solvent, is deposited on a glass substrate,
2. b) the glazing containing the substrate and the deposited solution is dried, and
3. c) at a temperature between 100 and 150 ° C.

The isocyanate (polyisocyanate, tri- and / or bi-isocyanate) reacts with the polyol as with the polyol function of the bisurea, which is thus incorporated in the polyurethane network.

• les fonctions hydroxy de la bisurée représentent 1 à 25, de préférence 3 à 22 % molaires des fonctions hydroxy de la totalité des polyols ;
• l'isocyanate est choisi parmi l'hexaméthylène-1,6-diisocyanate, un oligomère ou un homopolymère de celui-ci, et un diisocyanate aliphatique cyclique, seuls ou en mélange de plusieurs d'entre eux ;
• le polyol est choisi parmi les polyéthylènes glycol, polypropylène éther polyol et 1,4-butanediol, seuls ou en mélange de plusieurs d'entre eux ;
• la solution contient un catalyseur, de préférence le dilaurate de dibutylétain ;
• la solution présente un rapport molaire [NCO] /[OH] compris entre 0,7 et 1,3, de préférence 0,8 et 1,15.

According to preferred features of the process of the invention:

• the hydroxy functions of the bisurea represent 1 to 25, preferably 3 to 22 mol% of the hydroxy functions of all the polyols;
• the isocyanate is chosen from hexamethylene-1,6-diisocyanate, an oligomer or a homopolymer thereof, and a cyclic aliphatic diisocyanate, alone or as a mixture of several of them;
• the polyol is chosen from polyethylene glycol, polypropylene ether polyol and 1,4-butanediol, alone or as a mixture of several of them;
• the solution contains a catalyst, preferably dibutyltin dilaurate;
• the solution has an [NCO] / [OH] molar ratio of between 0.7 and 1.3, preferably 0.8 and 1.15.

Another subject of the invention consists in the use of a glazing unit comprising a hydrophilic layer as described above, for a land, air and aquatic transport vehicle, in particular for an electric vehicle or other motor vehicle, by example as windshield, rear window, side glazing or roof glazing, for building, interior mirrors, household appliances, street furniture, especially for the purpose of reducing moisture condensation on the glazing.

The invention is now illustrated by the following example.

EXAMPLE Chemical products

The isocyanates used in the formulation of the polyurethane network were supplied by Bayer. Desmodur® N3200 is a trifunctional isocyanate with a molecular weight of 480g.mol ^-1 . It is based on the biuret structure of diisocyanate hexamethylene. Desmodur W is a cyclic aliphatic diisocyanate with a molecular weight of 262 g.mol ^-1 . Their formulas are shown schematically below.

The isocyanates were kept under an inert atmosphere. The determination of the NCO groups was carried out by acid-base measurement according to standard NF EN ISO 14896.

The polyol used is a polyethylene glycol (PEG) of 200 g mol ^-1 . PEG as well as dibutyltin dilaurate (DBTL) used as a reaction catalyst are commercial products from Aldrich.

The polyester-functional, hydroxy-functional polydimethylsiloxane film-forming agent is BYK-370 and was supplied by BYK-Chemie GmbH.

Polyvinylpyrrolidone (PVP), which acts as an anti-fogging agent, is distributed by BASF under the brand name Luvitec® K90.

Finally the solvent of the formulation, the diacetone alcohol (DAA) comes from VWR.

Synthesis of bis-urea compounds

The bis-urea compounds are monomers comprising two urea functions, arranged around an aromatic core and linked to side alkyl chains. In order to incorporate them into the polyurethane network the side alkyl chains have been hydroxyl functionalized.

Trois monomères bis-urée ont été synthétisés à partir de toluène 2,4 diisocyanate (TDI) d'une part, de 6-amino-1-hexanol, 2-amino-1-butanol et amino-2-propanol d'autre part, tous achetés chez Aldrich. Le TDI a été conservé à 4°C dans le but d'éviter les réactions secondaires. Le dichlorométhane a été obtenu chez VWR et distillé et séché avant utilisation. Le tableau ci-dessous indique le N° attribué à chaque bis-urée dans la suite de l'exemple, les produits de départ de sa synthèse, une représentation schématique de sa formule et sa solubilité dans DAA. Tableau 1 - Composition des monomères bis-urées synthétisés Composé Diisocyanate Amino-alcool Formule Solubilité dans DAA (%mass) Bis-urée1 (Bis 1) TDI Amino-2-propanol

8 M=324.38g.mol^-1 Bis-urée4 (Bis 4) TDI 6-amino-1-hexanol

7.5 M=408.54g.mol^-1 Bis-urée5 (Bis 5) TDI 2-amino-1-butanol

2.4 M=352.44g.mol^-1 The synthesis is carried out in a single step by condensation between a diisocyanate and an amino alcohol in dichloromethane, according to the following reaction scheme.

Three monomers bis-urea were synthesized from toluene 2,4 diisocyanate (TDI) on the one hand, 6-amino-1-hexanol, 2-amino-1-butanol and amino-2-propanol on the other hand , all bought from Aldrich. TDI was stored at 4 ° C in order to avoid side reactions. Dichloromethane was obtained from VWR and distilled and dried before use. The table below indicates the number assigned to each bis-urea in the rest of the example, the starting materials of its synthesis, a schematic representation of its formula and its solubility in DAA. Table 1 - Composition of Synthesized Bisurea Monomers Compound diisocyanate Amino alcohol Formula Solubility in DAA (% mass) Bis-urea1 (Bis 1) TDI Amino-2-propanol

8 M = 324.38g.mol ^-1 Bis-urea4 (Bis 4) TDI 6-amino-1-hexanol

7.5 M = 408.54g.mol ^-1 Bis-urea5 (Bis 5) TDI 2-amino-1-butanol

2.4 M = 352.44g.mol ^-1

A solution of aminoalcohol (0.15 mol) in 100 ml of anhydrous CH ₂ Cl ₂ was added under nitrogen and at 0 ° C. to a solution of TDI (0.07 mol) in 250 ml of anhydrous CH ₂ Cl ₂ . The white precipitate obtained was then filtered and then washed with dichloromethane and recovered after evaporation of the solvent under pronounced vacuum. An NMR spectrum of the final product was finally made to verify the purity of the product.

Formulation

Upstream of the formulation, a stock solution containing 15% by weight of PVP in DAA was prepared by dissolution and stirring.

The formulations were prepared for a solids content of 35% by weight in the solvent.

Sample formulations

In a pillbox, the stock solution is weighed and then the calculated mass of PEG is pipetted. The solution is stirred at room temperature and the calculated mass of isocyanate is introduced into the mixture. The film-forming agent (BYK-370) and the catalyst (DBTL) are successively added with the appropriate amount of solvent. The final solution is stirred at room temperature.

Formulations with bis-urea

The bis-urea compounds synthesized are dissolved at ambient temperature and with stirring in the DAA. The mass concentration of bis-urea in DAA depends on the molar amount of bis-urea that it is desired to introduce into the network. The calculated masses of stock solution, PEG, isocyanate, BYK and DBTL are respectively added to the solution and stirred between each addition.

The thickness of the wet film deposited on the substrate is 100 μm.

The formulated films were then stored in a closed, ventilated oven. The solvent was evaporated at 50 ° C and the baking step was carried out at 120 ° C. The thickness of the film after firing is at 40 μm. The composition of the main formulations explained is reported in the table below.

In all cases, the thickness of the hydrophilic layer is 40 microns dry.

The terms "titration 21 (or 22)" indicate a mass proportion of the triisocyanate and optionally 21 or 22% diisocyanate in the deposited solution.

• 0,2 à 7 % en masse (3,5 % dans l'exemple) de polyvinylpyrrolidone, et
• 0,001 à 1,5 % en masse (0,13 % dans l'exemple) de BYK-370.

It also contains:

• 0.2 to 7% by weight (3.5% in the example) of polyvinylpyrrolidone, and
• 0.001 to 1.5% by weight (0.13% in the example) of BYK-370.

The amounts of DBTL used vary from 0.001 to 1% by weight (0.01% in the example).

Reference examples indicate control formulations free of bisurea.

The amounts of PEG and bisurea are such that the concentration of hydroxy functions is equal to the concentration of isocyanate functions.

The scratch resistance of the layers proves to be a paramount parameter for many applications. The scratch tests were carried out on a Universal Scratch Test Model 413 (Erichsen DIN53799) using a spherical geometry -0.75mm- metal tip. A progressive load ranging from 1 to 10N was applied to the layer to evaluate the performance thereof. The scratch resistance of the layer is given by the lowest load causing a mark visible to the naked eye on the coating.

Two phenomena are observed: autonomous self-healing and stimulated self-healing.

On some tests, scratches appear from a certain force applied to the Erichsen test, but gradually disappear, however up to a maximum value of this applied force. The domain between the force of appearance of scratches and this maximum value of disappearance of scratches is that of autonomous self-healing.

On other tests, or even in some cases self-repaired self-repair, the scratches disappear only by a contact of 30 seconds with water, removed by wiping for example, after these 30 seconds; however, this phenomenon is again observed only up to a certain maximum value of the force applied to the Erichsen test, defining the stimulated self-healing domain.

The scratch resistance of the layers is first evaluated under dry conditions. The results are recorded in the form of a histogram represented at Figure 1 attached. They mainly concern the layers formed without diisocyanate Desmodur W as starting material.

Bisure 1 of A1 provides an increase in scratch resistance by self-healing stimulated (about 3 min), relative to A0.

The bisure 4 of A2 provides an increase in scratch resistance by self-healing (about 2 minutes), relative to A0.

The bisurea of A'6 provides an increase in self-healing scratch resistance (about 3 minutes) compared to A'0.

Similar trends are observed between the two groups titration measures "titration 21" and "titration 22", with a better resistance to scratching for the first city.

The wet scratch resistance of the layers formed partly from the diisocyanate Desmodur W is now evaluated by the Erichsen test. The results are recorded in the histogram shown in FIG. Figure 2 .

An improvement in the scratch resistance is observed when 10 mol% of the diols consist of bisurea: the appearance of scratches occurs at a lower value of the force applied to the Erichsen test, but there is self-repair of the scratches until at a higher value of this force than the appearance value of the scratches in the absence of bisurea.

The use of bisurea 1 in B1 provides stimulated self-repair (about 3 min).

The use of bisurea 4 in B2 provides autonomous self-healing (over 2 min) followed by stimulated self-repair.

The dry scratch resistance of the hydrophilic layers formed without diisocyanate is better than the scratch resistance in wet conditions of the hydrophilic layers for which part of the triisocyanate has been replaced by diisocyanate (comparison BO / A0, B1 / A1, B2 / A2, B'4 / A'4, B'5 / A'5).

The scratch resistance is again better for the titration tests 21 than for the titration tests 22.

In a second series of tests, part of the PEG is replaced by the trifunctional polypropylene ether polyol marketed by Bayer under the trade name Desmophen® 1380 BT. The composition of the formulations is reported in the table below.

The scratch resistance results are recorded in the Figure 3 in annex. It is again observed that a content of bisurea increases the scratch resistance by autonomous self-repair.

Claims (15)

1. A glazing unit comprising a hydrophilic layer comprising a polyurethane network incorporating at least one of the compounds bis-urea 1, respectively bis-urea 4, respectively bis-urea 5 obtained from toluene-2,4-diisocyanate (TDI) on the one hand, 2-aminopropanol, respectively 6-amino-1-hexanol, respectively 2-amino-1-butanol and on the other hand.
2. The glazing unit as claimed in claim 1, characterized in that the hydrophilic layer contains polyvinylpyrrolidone.
3. The glazing unit as claimed in one of the preceding claims, characterized in that the hydrophilic layer contains a film-forming agent.
4. The glazing unit as claimed in claim 3, characterized in that the film-forming agent contains at least one polydimethylsiloxane, preferably modified with a polyester, in particular comprising a hydroxyl function.
5. The glazing unit as claimed in claim 3 or 4, characterized in that the hydrophilic layer contains at least 75% to 99% by weight of polyurethane, 1% to 15% by weight of polyvinylpyrrolidone, and 0.01% to 3% by weight of film-forming agent.
6. The glazing unit as claimed in one of claims 2 to 5, characterized in that the weight-average molecular weight of the polyvinylpyrrolidone is from 1.1 × 10⁶ to 1.8 × 10⁶ g/mol.
7. The glazing unit as claimed in one of the preceding claims, characterized in that the hydrophilic layer has a thickness of between 0.1 and 250 µm, preferably 1 and 100 µm, and particularly preferably 3 and 50 µm.
8. The glazing unit as claimed in one of the preceding claims, characterized in that the hydrophilic layer is connected to a glass substrate with interposition of an adhesion primer which contains at least one aminosilane.
9. A process for manufacturing a glazing unit comprising a hydrophilic layer as claimed in one of the preceding claims, wherein:

   a) a solution containing at least one isocyanate, one polyol and one bis-urea comprising a polyol function, polyvinylpyrrolidone, a film-forming agent and a solvent is deposited on a glass substrate,

   b) the glazing unit containing the substrate and the deposited solution is dried, and

   c) subjected to a temperature of between 100 and 150°C.
10. The process as claimed in claim 9, characterized in that the hydroxyl functions of the bis-urea represent 1 to 25, preferably 3 to 22 mol% of the hydroxyl functions of all the polyols.
11. The process as claimed in claim 9, characterized in that the isocyanate is chosen from hexamethylene-1,6-diisocyanate, an oligomer or a homopolymer thereof, and a cyclic aliphatic diisocyanate, alone or as a mixture of several of them.
12. The process as claimed in claim 9, characterized in that the polyol is chosen from polyethylene glycols, polypropylene ether polyol and 1,4-butanediol, alone or as a mixture of several of them.
13. The process as claimed in claim 9, characterized in that the solution contains a catalyst, preferably dibutyltin dilaurate.
14. The process as claimed in claim 9, characterized in that the solution has an [NCO]/[OH] molar ratio of between 0.7 and 1.3, preferably 0.8 and 1.15.
15. The use of a glazing unit comprising a hydrophilic layer as claimed in one of claims 1 to 8, for a terrestrial, airborne or aquatic transportation vehicle, in particular for an electric vehicle or other motor vehicle, for example as a windshield, rear window, side glazing unit or roof glazing unit, for construction, interior fittings, mirrors, electrical goods and street furniture, in particular with the aim of reducing the condensation of moisture on the glazing unit.

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